Methods of reducing a concentration of formaldehyde in aqueous solutions of sugar carbonyls

ABSTRACT

A method of reducing a concentration of formaldehyde in an aqueous solution containing formaldehyde, hydroxyacetaldehyde and other sugar carbonyls is provided. The method includes adding an amino acid to the aqueous solution and maintaining the aqueous solution at a temperature for a duration sufficient for the formaldehyde and the amino acid to react according to a Maillard reaction to produce a final concentration of formaldehyde and a final concentration of hydroxyacetaldehyde in the aqueous solution. The final concentration of formaldehyde is substantially lower than an initial concentration of formaldehyde and the final concentration of hydroxyacetaldehyde is not substantially lower than an initial concentration of hydroxyacetaldehyde. An aqueous solution and a method of browning a foodstuff are also provided.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.15/491,339, filed on Apr. 19, 2017, the contents of which isincorporated herein by reference in its entirety.

TECHNICAL FIELD

The embodiments disclosed herein relate to methods of providing anaqueous solution with a reduced concentration of formaldehyde, and morespecifically, to methods of providing an aqueous solution with a reducedconcentration of formaldehyde, the solution includinghydroxyacetaldehyde and other sugar carbonyl compounds.

BACKGROUND

Pyrolysis of sugars (such as glucose) is a known reaction that has beenshown to be useful for producing solutions comprisinghydroxyacetaldehyde (also called glycolaldehyde). For example, as shownin U.S. Pat. No. 7,094,932, the pyrolysis of glucose can providecommercially useful yields of aqueous solutions comprisinghydroxyacetaldehyde. These aqueous solutions can be useful in the foodindustry as natural browners (e.g. for meats, fish, and bakery items),as flavor precursors, as proteinaceous crosslinkers and as antimicrobialsolutions.

During the pyrolysis of glucose, formaldehyde is produced as anundesirable by-product. Formaldehyde is particularly undesirable inaqueous solutions comprising hydroxyacetaldehyde intended to be used inthe food industry as gaseous formaldehyde is well known to be ahazardous substance to humans.

U.S. Patent App. No. 2016/0002137 teaches one method of removingformaldehyde from a solution comprising hydroxyacetaldehyde. The methoduses reactive distillation in the presence of an alcohol and a catalystto remove formaldehyde from the solution comprising hydroxyacetaldehyde,where the formaldehyde is selectively acetalized. Although the productof the reactive distillation is substantially free of formaldehyde, theformaldehyde acetals formed during the reactive distillation must beseparately removed from the product solution prior to use of the productsolution in the subsequent catalytic hydrogenation ofhydroxyacetaldehyde to ethylene glycol.

Accordingly, there is a need for an improved method of reducing aconcentration of formaldehyde in aqueous solutions comprising sugarcarbonyls.

SUMMARY

In accordance with one aspect, a method of reducing a concentration offormaldehyde in an aqueous solution containing formaldehyde,hydroxyacetaldehyde and other sugar carbonyls is provided. The methodincludes adding an amino acid to the aqueous solution and maintainingthe aqueous solution at a temperature for a duration sufficient for theformaldehyde and the amino acid to react according to a Maillardreaction to produce a final concentration of formaldehyde and a finalconcentration of hydroxyacetaldehyde in the aqueous solution. The finalconcentration of formaldehyde is substantially lower than an initialconcentration of formaldehyde in the aqueous solution and the finalconcentration of hydroxyacetaldehyde is not substantially lower than aninitial concentration of hydroxyacetaldehyde in the aqueous solution.

In another aspect of the method, the final concentration of formaldehydeis less than 50% of the initial concentration of formaldehyde.

In another aspect of the method, the final concentration of formaldehydeis less than 10% of the initial concentration of formaldehyde.

In another aspect of the method, the final concentration ofhydroxyacetaldehyde is more than 50% of the initial concentration ofhydroxyacetaldehyde.

In another aspect of the method, the final concentration ofhydroxyacetaldehyde is more than 80% of the initial concentration ofhydroxyacetaldehyde.

In another aspect of the method, the amino acid is one of glycine andcysteine.

In another aspect of the method, the amino acid is cysteine.

In another aspect of the method, the aqueous solution has an initialamount of formaldehyde and an amount of amino acid is added to theaqueous solution, wherein a molar ratio of the amount of amino acidadded to the solution to the initial amount of formaldehyde is in arange of 1:2 to 1:10.

In another aspect of the method, the molar ratio is in a range of 1:3 to1:5.

In another aspect of the method, the other sugar carbonyls furthercomprise one or more of glyoxal, pyruvaldehyde and acetol.

In another aspect of the method, the aqueous solution has an initialconcentration of glyoxal, an initial concentration of pyruvaldehyde, aninitial concentration of acetol, a final concentration of glyoxal, afinal concentration pyruvaldehyde and a final concentration acetol;wherein the final concentration of glyoxal is not substantially lowerthan the initial concentration of glyoxal, the final concentration ofpyruvaldehyde is not substantially lower than the initial concentrationof pyruvaldehyde and the final concentration of acetol is notsubstantially lower than the initial concentration of acetol.

In another aspect, a method of browning a foodstuff is provided. Themethod includes preparing an aqueous solution of sugar carbonyls bypyrolysis of sugars, the sugar carbonyls comprising formaldehyde andhydroxyacetaldehyde, the aqueous solution having an initialconcentration of formaldehyde and an initial concentration ofhydroxyacetaldehyde, adding an amino acid to the aqueous solution,maintaining the aqueous solution at a temperature for a durationsufficient for the formaldehyde and the amino acid to react according toa Maillard reaction to produce a final concentration of formaldehyde anda final concentration of hydroxyacetaldehyde in the aqueous solution,wherein the final concentration of formaldehyde is substantially lowerthan the initial concentration of formaldehyde and the finalconcentration of hydroxyacetaldehyde is not substantially lower than theinitial concentration of hydroxyacetaldehyde, and heating the aqueoussolution with the final concentration of formaldehyde in the presence ofthe foodstuff to brown the foodstuff.

In another aspect of the method, the final concentration of formaldehydeis less than 10% of the initial concentration of formaldehyde.

In another aspect of the method, the final concentration ofhydroxyacetaldehyde is more than 80% of the initial concentration ofhydroxyacetaldehyde.

In another aspect of the method, the amino acid is one of glycine andcysteine.

In another aspect of the method, the amino acid is cysteine.

In another aspect, an aqueous solution of sugar carbonyls prepared bypyrolysis of sugars is provided. The sugar carbonyls includeformaldehyde and hydroxyacetaldehyde. The aqueous solution has a finalconcentration of formaldehyde that is substantially lower than aninitial concentration of formaldehyde and a final concentration ofhydroxyacetaldehyde that is not substantially lower than an initialconcentration of hydroxyacetaldehyde. The final concentration offormaldehyde and the final concentration of hydroxyacetaldehyde areproduced by adding an amino acid to the aqueous solution and maintainingthe aqueous solution at a temperature for a duration sufficient for theformaldehyde and the amino acid to react according to a Maillardreaction to produce the final concentration of formaldehyde and thefinal concentration of hydroxyacetaldehyde in the aqueous solution.

In another aspect of the solution, the final concentration offormaldehyde is less than 10% of the initial concentration offormaldehyde.

In another aspect of the solution, the final concentration ofhydroxyacetaldehyde is more than 80% of the initial concentration ofhydroxyacetaldehyde.

In another aspect of the solution, the amino acid is cysteine.

Additional aspects will be apparent in view of the description whichfollows. It should be understood however that the detailed descriptionand the specific examples, while indicating preferred embodiments of theinvention, are given by way of illustration only, since various changesand modifications will become apparent to those skilled in the art fromthis detailed description.

DETAILED DESCRIPTION

Various methods will be described below to provide an example of one ormore embodiments. No embodiment described below limits any claimedembodiment and any claimed embodiment may cover methods that differ fromthose described below. The claimed embodiments are not limited tomethods having all of the features of any one method described below orto features common to multiple or all of the methods described below.Any embodiment disclosed below that is not claimed in this document maybe the subject matter of another protective instrument, for example, acontinuing patent application, and the applicants, inventors or ownersdo not intend to abandon, disclaim or dedicate to the public any suchembodiment by its disclosure in this document.

Herein, the term “Maillard reaction” refers to a chemical reactionbetween amino acids and reducing sugars. In the food industry, Maillardreactions are used as a form of non-enzymatic browning, where carbonylgroups of sugar-carbonyl compounds react with nucleophilic amino groupsof amino acids in proteins to form a complex mixture of poorlycharacterized molecules. In food processing applications, the complexmixture of poorly characterized molecules can be responsible for a rangeof aromas, colors and flavors. Maillard reactions can include a seriesof consecutive reactions affecting food and biopharmaceutical productsinvolving dozens of compounds. In the process, hundreds of differentflavor compounds can be created. These compounds, in turn, break down toform yet more new flavor compounds, and so on. Each type of food has avery distinctive set of flavor compounds that are formed during theMaillard reaction. It is these same compounds that flavor scientistshave used over the years to make a variety of flavors.

In one example, a Maillard reaction begins with a carbonyl group of asugar reacting with an amino group of an amino acid, producingN-substituted glycosylamine and water. The unstable glycosylamine canthen undergo Amadori rearrangement, forming an Amadori compound (e.g.ketosamines). Amadori rearrangement is an organic reaction describingthe acid or base catalyzed isomerization or rearrangement reaction ofthe N-glycoside of an aldose or the glycosylamine to the corresponding1-amino-1-deoxy-ketose. Returning to the Mallard reaction mechanism,there are several ways for the ketosamines to react further onceundergoing Amadori rearrangement. For example, the ketosamines canproduce two water molecules and reductones. Alternatively, diacetyl,aspirin, pyruvaldehyde and other short-chain sugar carbonyl hydrolyticfission products can be formed. Alternatively stiff, brown nitrogenouspolymers and melanoidins can be produced. Melanoidins are complex, notwell-characterized, nitrogeneous, water-soluble co-polymers which areresponsible for brown coloration of foods. Specifically, melanoidinpigments are responsible for different shades of browning of smoked,baked, roasted and/or grilled foods, for example. Each type of food hasa very distinctive set of flavor compounds and a different set ofmelanoidins are formed during the Maillard reaction based on the type offood.

Herein, the term “sugar carbonyl compounds” or “sugar carbonyls” refersto low molecular weight carbonyl compounds such as but not limited toformaldehyde, hydroxyacetaldehyde, glyoxal, pyruvaldehyde (also referredto as methylglyoxal) and acetol.

This application describes methods that use a Maillard reaction toreduce a concentration of formaldehyde in aqueous solutions with sugarcarbonyls.

In one embodiment, the aqueous solution has an initial concentration offormaldehyde. For reference, formaldehyde is represented by thefollowing formula I:

The initial concentration of formaldehyde in the aqueous solution can bein a range of 1 to 6 wt %. In an embodiment, the formaldehyde has aninitial concentration in a range of 2 to 6 wt % and more specifically ina range of 3 to 6 wt % of the total weight of the aqueous solution.

The initial concentration of formaldehyde is reduced by adding an aminoacid to the solution and maintaining the solution at a temperature for aduration for a Maillard reaction to occur and produce a finalconcentration of formaldehyde in the aqueous solution.

The final concentration of formaldehyde in the aqueous solution issubstantially lower than the initial concentration of formaldehyde inthe aqueous solution. Herein, a final concentration of a solute being“substantially lower” than an initial concentration of a solute refersto the final concentration of the solute being 50% or less of theinitial concentration of the solute.

In an embodiment, the final concentration of formaldehyde in the aqueoussolution may be less than 50% of the initial concentration offormaldehyde in the aqueous solution. In another embodiment, the finalconcentration of formaldehyde in the aqueous solution may be less than40% of the initial concentration of formaldehyde in the aqueoussolution. In another embodiment, the final concentration of formaldehydein the aqueous solution may be less than 30% of the initialconcentration of formaldehyde in the aqueous solution. In anotherembodiment, the final concentration of formaldehyde in the aqueoussolution may be less than 20% of the initial concentration offormaldehyde in the aqueous solution. In another embodiment, the finalconcentration of formaldehyde in the aqueous solution may be less than10% of the initial concentration of formaldehyde in the aqueoussolution. In another embodiment, the final concentration of formaldehydein the aqueous solution may be less than 5% of the initial concentrationof formaldehyde in the aqueous solution.

In an embodiment, the final concentration of formaldehyde in the aqueoussolution may be in a range of 0 to 2 wt % and more specifically in arange of 0 to 1 wt % of the total weight of the aqueous solution. Inanother embodiment, the final concentration of formaldehyde in theaqueous solution may be less than 0.5 wt % of the total weight of theaqueous solution. In another embodiment, the final concentration offormaldehyde in the aqueous solution may be less than 0.2 wt % of thetotal weight of the aqueous solution.

The aqueous solution also includes sugar carbonyls such ashydroxyacetaldehyde. For reference, hydroxyacetaldehyde is representedby the following formula II:

An initial concentration of hydroxyacetaldehyde in the aqueous solutioncan be in a range of 4 to 50 wt %. In an embodiment, the initialconcentration of hydroxyacetaldehyde in the aqueous solution may be in arange of 20 to 30 wt % and more specifically in a range of 24 to 26 wt %of the total weight of the aqueous solution.

The initial concentration of hydroxyacetaldehyde in the aqueous solutionis not substantially reduced by adding the amino acid to the aqueoussolution and maintaining the aqueous solution at a temperature for aduration for the Maillard reaction to occur and produce a finalconcentration of hydroxyacetaldehyde in the aqueous solution.

The final concentration of hydroxyacetaldehyde in the aqueous solutionis not substantially lower than the initial concentration ofhydroxyacetaldehyde in the aqueous solution. Herein, a finalconcentration of a solute being “not substantially lower” than aninitial concentration of a solute means that the final concentration ofthe solute is 50% or more of the initial concentration of the solute.

In an embodiment, the final concentration of hydroxyacetaldehyde in theaqueous solution may be more than 50% of the initial concentration ofhydroxyacetaldehyde in the aqueous solution. In another embodiment, thefinal concentration of hydroxyacetaldehyde in the aqueous solution maybe more than 60% of the initial concentration of hydroxyacetaldehyde inthe aqueous solution. In another embodiment, the final concentration ofhydroxyacetaldehyde in the aqueous solution may be more than 70% of theinitial concentration of hydroxyacetaldehyde in the aqueous solution. Inanother embodiment, the final concentration of hydroxyacetaldehyde inthe aqueous solution may be more than 80% of the initial concentrationof formaldehyde in the aqueous solution.

In an embodiment, the final concentration of hydroxyacetaldehyde in theaqueous solution may be in a range of 4 to 50 wt %, more specifically ina range of 18 to 30 wt % and more specifically in a range of 20 to 25 wt% of the total weight of the aqueous solution.

In an embodiment, a molar ratio of an initial amount ofhydroxyacetaldehyde in the aqueous solution to an initial amount offormaldehyde in the aqueous solution may be in a range of 10:1 to 2:1and more specifically in a range of 5:1 to 3:1. In another embodiment, amolar ratio of a final amount of hydroxyacetaldehyde in the aqueoussolution to a final amount of formaldehyde in the aqueous solution maybe at least 50:1.

In an embodiment, the sugar carbonyls may include sugar carbonyls otherthan formaldehyde and hydroxyacetaldehyde. For example, the sugarcarbonyls may further comprise one or more of glyoxal, pyruvaldehyde andacetol. The glyoxal may have an initial concentration in the aqueoussolution in a range of 0.5 to 5 wt % and more specifically in a range of1 to 5 wt % of the total weight of the aqueous solution. Thepyruvaldehyde may have an initial concentration in the aqueous solutionin a range of 0 to 5 wt % and more specifically in a range of 0 to 2 wt% of the total weight of the aqueous solution. The acetoi may have aninitial concentration in the aqueous solution in a range of 0 to 5 wt %and more specifically in a range of 0 to 3 wt % of the total weight ofthe aqueous solution. The glyoxal, pyruvaldehyde and acetol may combineto have a combined initial concentration in the aqueous solution in arange of 1 to 20 wt %, more specifically in a range of 1 to 15 wt % andmore specifically in a range of 1 to 10 wt % of the total weight of theaqueous solution.

In an embodiment, each of the initial concentrations of glyoxal,pyruvaldehyde and acetol in the aqueous solution may not besubstantially reduced by adding the amino acid to the solution andmaintaining the solution at a temperature for a duration for theMaillard reaction to occur and produce final concentrations of each ofthe glyoxal, pyruvaldehyde and acetol in the aqueous solution.

In an embodiment, the final concentration of glyoxal in the aqueoussolution may be in a range of 1 to 5 wt % and more specifically in arange of 2 to 5 wt % of the total weight of the aqueous solution. Thefinal concentration of pyruvaldehyde in the aqueous solution may be in arange of 0 to 5 wt % and more specifically in a range of 0 to 2 wt % ofthe total weight of the aqueous solution. The final concentration ofacetol in the aqueous solution may be in a range of 0 to 5 wt % and morespecifically in a range of 0 to 3 wt % of the total weight of theaqueous solution. The glyoxal, pyruvaldehyde and acetol may combine tohave a combined final concentration in the aqueous solution in a rangeof 1 to 10 wt % and more specifically in a range of 2 to 8 wt % of thetotal weight of the aqueous solution.

In an embodiment, the aqueous solution may further comprise water havingan initial concentration in a range of 10 to 90 wt % and morespecifically in a range of 50 to 70 wt % of the total weight of theaqueous solution and a final concentration in a range of 10 to 90 wt %and more specifically in a range of 50 to 70 wt % of the total weight ofthe aqueous solution.

As previously described, to reduce the initial concentration offormaldehyde in the aqueous solution, an amino acid is added to theaqueous solution.

The amino acid added to the aqueous solution may be selected from agroup consisting of: alanine, arginine, asparagine, cysteine, glutamine,glycine, histidine, lysine, methionine, proline, serine, tryptophan,tyrosine, and valine. In one embodiment, the amino acid is selected froma group consisting of glycine and cysteine. In another embodiment, theamino acid can be one of glycine and cysteine. In another embodiment,the amino acid can be cysteine.

In an embodiment, the amino acid is added to the aqueous solution in anamount sufficient to produce a Maillard reaction between the amino acidand the formaldehyde. In one example, the amount of amino acid added tothe aqueous solution is in a range of 1 to 5 wt % and more specificallyin a range of 2 to 4 wt % of the total weight of the aqueous solution.In another example, the amount of amino acid added to the aqueoussolution is such that a molar ratio of the amount of amino acid added tothe aqueous solution to the amount of formaldehyde in the aqueoussolution is in a range of 1:2 to 1:10. In another example, the amount ofamino acid added to the aqueous solution is such that a molar ratio ofthe amino acid added to the aqueous solution to the formaldehyde in theaqueous solution is in a range of 1:3 to 1:5.

After adding the amino acid to the aqueous solution, the aqueoussolution is maintained at a temperature for a duration sufficient toreduce the concentration of the formaldehyde in the aqueous solutionresulting from the Maillard reaction between the amino acid and theformaldehyde. Upon mixing, the amino acid may dissolve in the aqueoussolution.

In an embodiment the temperature of the aqueous solution may bemaintained in a range of ˜15° C. to 30° C. (e.g. room temperature) andmore specifically in a range of ˜18° C. to 22° C. to reduce theconcentration of the formaldehyde in the aqueous solution as a result ofthe Maillard reaction between the amino acid and the formaldehyde.

In another embodiment, the temperature of the aqueous solution may bemaintained for a duration in a range of 0 to 96 hours and morespecifically from 48 to 96 hours to reduce the concentration of theformaldehyde in the aqueous solution as a result of the Maillardreaction between the amino acid and the formaldehyde.

In an embodiment, the amount of amino acid added to the aqueous solutionis such that a molar ratio of the amount of amino acid added to theaqueous solution to the initial amount of formaldehyde in the aqueoussolution is in a range of 1:2 to 1:10, and more specifically in a rangeof 1:3 to 1.5.

In an embodiment, after the Maillard reaction, the aqueous solution mayfurther comprise melanoidins. Melanoidins are a product of the Maillardreaction. The structure of melanoidins is poorly defined as theseheterogeneous macromolecular compounds cannot be individuallycharacterized. Melanoidins include polymeric and colored final productsof the Maillard reaction. Melanoidins can include furan ring- andnitrogen-containing co-polymers that vary in structure depending on thereactants and conditions of their preparation. Melanoidins can beresponsible for a brown or red colour of roasted, baked, toasted,grilled, charred or browned foods, and are also common in many dietaryliquids such as soy sauce, honey, wine, beer and coffee Melanoidins canbe formed by cyclizations, dehydrations, retroaldolisations,rearrangements, isomerisations, and condensations that occur over thecourse of the Maillard reaction.

In one example, after the Maillard reaction, the aqueous solution maycomprise melanoidins having a concentration in a range of 0-20 wt % andmore specifically in a range of ˜8-15 wt %. In another embodiment, afterthe Maillard reaction, the aqueous solution may comprise melanoidinshaving a concentration in a range of ˜8-15 wt % when the initialconcentration of formaldehyde in the aqueous solution was ˜4 wt % andthe initial concentration of hydroxyacetaldehyde in the aqueous solutionwas ˜25 wt %.

In another embodiment, after the Maillard reaction, the aqueous solutionmay have a red colour. Optionally, the red colour of the aqueoussolution can be removed by any known techniques such as but not limitedto activated carbon or ion exchange resins application, membraneseparation, nano-filtration or reverse osmosis.

In another embodiment, after providing the aqueous solution with thereduced concentration of formaldehyde, the aqueous solution may be usedfor browning foodstuffs. Herein, the term foodstuff refers to asubstance suitable for consumption as food.

In an embodiment, a foodstuff may be browned by heating the foodstuff inthe presence of the aqueous solution at a temperature for a durationsufficient to brown the foodstuff.

In an embodiment, of the method of browning a foodstuff, an aqueoussolution of sugar carbonyls can be prepared by pyrolysis of sugars. Thesugar carbonyls include formaldehyde and hydroxyacetaldehyde and theaqueous solution has an initial concentration of formaldehyde and aninitial concentration of hydroxyacetaldehyde as previously described. Anamino acid is added to the aqueous solution and the aqueous solution ismaintained at a temperature for a duration sufficient for theformaldehyde and the amino acid to react according to a Maillardreaction to produce a final concentration of formaldehyde and a finalconcentration of hydroxyacetaldehyde in the aqueous solution aspreviously described. The final concentration of formaldehyde issubstantially lower than the initial concentration of formaldehyde andthe final concentration of hydroxyacetaldehyde is not substantiallylower than the initial concentration of hydroxyacetaldehyde.

In an embodiment, the aqueous solution with the final concentration offormaldehyde may be heated in the presence of the food stuff to atemperature in a range of 60-150° C. In another embodiment, thefoodstuff may be added to a heated aqueous solution while the aqueoussolution is maintained at a temperature for a duration sufficient tocook the foodstuff. In an embodiment, the duration can be in a range of2-5 minutes.

In an embodiment, heating the foodstuff in the aqueous solution with thefinal concentration of formaldehyde can produce a brownish colour on anexterior surface of the foodstuff, or applying the browning solution anexterior by other means.

In an embodiment, the foodstuff can be selected from: meat (e.g.sausage, bacon, etc.) fish, or baked items (e.g. a bakery or a pastryitem).

EXAMPLES

In the following Examples, liquid products were quantified by HPLCanalysis (Agilent, 1200 Series). The analytes were separated on a BioRadAminex HPX-87H column operating at 30° C. The eluent was a 0.005 Maqueous H₂SO₄, at a flow rate of 0.6 mL/min. The analytes werequantified using Waters 410 RI detector against standard samples.

Example 1

To demonstrate reactivity between an amino acid and formaldehyde whenthe formaldehyde is in solution with hydroxyacetaldehyde, 1.5 moles ofcysteine (product from Aldrich-Sigma) were added to a commerciallyavailable browning solution (ScanGold® distributed by Azelis) comprising3.5 moles of hydroxyacetaldehyde and 1 mole of formaldehyde having a pHof ˜2.5.

After 3 days at room temperature (e.g. between ˜15-30° C.), a sample ofthe resulting aqueous solution was analyzed to determine itscomposition.

Formaldehyde was not present in the resulting aqueous solution and lessthan 0.5 moles of hydroxyacetaldehyde was present. Melanoidin formationwas also demonstrated. The resulting aqueous solution had a dark redappearance as expected for browning reaction and was not pungent.

Example 2

To demonstrate reactivity between an amino acid and formaldehyde whenthe formaldehyde is in solution with hydroxyacetaldehyde and other sugarcarbonyl compounds, cysteine was added to a commercially availablesolution comprising ˜4.5 wt % formaldehyde and ˜30% hydroxyacetaldehydesuch that the cysteine had a concentration of 3.6 wt % in the resultingaqueous solution. The solution was mixed until fully solubilized.

After 24 hours at room temperature (e.g. between ˜15-30° C.), theformaldehyde concentration of the resulting solution was 1.5 wt % andthe hydroxyacetaldehyde concentration of the resulting solution wasstill above 20 wt %.

Recalculating above results, one can see that roughly one mole ofcysteine (molecular weight of 121.16 g/mol) is needed to react withapproximately four moles of formaldehyde (molecular weight of 30.031g/mol) with some losses of other carbonyls.

Example 3

In another example, 4.14 wt % of cysteine was added to a solution having3.18 wt % of formaldehyde. No other carbonyls were present. After 4days, white crystals appeared but the solution remained transparent andcolourless. The formaldehyde concentration of the solution was reducedto 2.12 wt %. No browning reaction occurred. Based on the weightpercentages of cysteine and formaldehyde and the molecular weights ofcysteine and formaldehyde (provided above), it was determined that 0.034moles of cysteine had reacted with 0.033 moles of formaldehyde (e.g. amolar ratio of ˜1:1).

Example 4

In another example, cysteine was added at 4.0 wt % to a commerciallyavailable water-based solution containing sugar-carbonyls (ScanGold®distributed by Azelis). The initial water concentration of the solutionwas 65 wt %.

The product produced by the reaction between the cysteine and thecommercially-available solution was stored at room temperature andre-analyzed over various time intervals. The results are provided inTable 1.

TABLE 1 Carbonyl concentrations over time. Initial concentrationConcentration Concentration Concentration after (wt %) after 2 hrs (wt%) after 24 hrs (wt %) 4 days (wt %) Hydroxyacetaldehyde 25.5 22.2 20.120.0 Formaldehyde 3.4 1.6 <0.6 <0.5 Glyoxal 1.8 1.5 1.6 1.6 Acetol 1.31.1 1.1 1.1

The colour of the sample darkened over time to a dark, red color. After4 days, the concentration of hydroxyacetaldehyde in the productstabilized and the pungent odour of formaldehyde was diminished.

Example 5

A variety of amino-acids were added in amounts of ˜4.0 wt % to acommercially available water solution having the composition provided inTable 2:

TABLE 2 Composition of a commercially-available aqueous solution.Concentration (wt %) Hydroxyacetaldehyde 25.3 Formaldehyde ~3.3 Glyoxal~2.0 Methylglyoxal <1.0 (pyruvaldehyde) Acetol ~1.4 Water ~65.0

All of the amino-acids used in the Examples described herein wereobtained from Sigma-Aldrich.

Products of the commercially available solution after the addition ofeach of the amino acids listed in Table 3 (below) were kept for 4 daysat room temperature and analyzed to determine the concentrations tohydroxyacetaldehyde and formaldehyde therein. The results are providedin Table 3:

TABLE 3 Results of hydroxyacetaldehyde and formaldehyde in the presenceof various amino acids after 4 days. Formaldehyde Hydroxyacetaldehydeconcentration concentration after after Colour of product Amino acid 4days (wt %) 4 days (wt %) solution Glutamine 23.2 1.4 red Asparagine22.5 1.0 red Arginine 20.5 1.2 red Histidine 20.5 1.7 red Tryptophan20.5 1.1 solubility issue, orange Glycine 20.5 1.2 red-dark Serine 20.51.5 red Lysine 20.2 0.8 red, deposit formed Alanine 19.7 1.0 red-darkProline 23 2.5 yellow Methionine 22.5 1.5 red Valine 23.5 1.2 redTyrosine 23.5 3.3 yellow, not well soluble Cysteine 20 <0.2 red-dark

It should be noted that the glyoxal, methylglyoxal and acetolconcentrations in the product solutions did not change significantlyfrom the original commercially available solution over the 4 day period.In the presence of hydroxyacetaldehyde, glyoxal, methylglyoxal andacetol, apart from tyrosine, all of the amino-acids tested affected theformaldehyde concentration of the product solution and contributed tothe formation of brown/red co-polymers. Cysteine appeared to be the mostefficient reducer of formaldehyde concentration.

Example 6

In another example, various amounts of cysteine (shown in Table 4 asweight percentages of the aqueous solution) were added to a solutioncomprising 24.9 wt % hydroxyacetaldehyde, 3.0 wt % formaldehyde, 22 wt %glyoxal, 1.5 wt % methylglyoxai and 1.4 wt % acetol. The samples reactedfor ˜3 days. The results are shown in Table 4.

TABLE 4 Hydroxyacetaldehyde and formaldehyde concentrations of productaqueous solutions after the addition of various amounts of cysteine.Cysteine Hydroxyacetaldehyde Formaldehyde (wt %) (wt %) (wt %) Colour3.8 20 <0.2 red, very dark 3.4 21 <0.5 red, very dark 2.7 22 <1.0 red1.6 22.5 1.7 orange/yellow

The results appear to confirm the findings of previous Example 2 where aspecific amount of cysteine to reduce the concentration of formaldehydein the product aqueous solution and preserving (e.g. substantiallypreserving) the concentration of other sugar-carbonyls in the aqueoussolution was 1 mole of cysteine for every 4 moles of formaldehyde in theoriginal aqueous solution. It should further be noted that sample with3.8 wt % of cysteine contained less than 0.04 wt % of formaldehyde.

As noted in Table 4, several of the sample solutions have a red colourafter the Maillard reaction. The red colour can be removed by anyappropriate, known technique such as but not limited to activated carbonor ion exchange resin applications, membrane separation, nano-filtrationand/or reverse osmosis.

Example 7

In another example, testing similar to that described in Example 6 wasconducted with another amino acid: glycine.

The initial aqueous solution to which glycine was added had acomposition of 25.5 wt % hydroxyacetaldehyde, 3.4 wt % formaldehyde, 2.0wt % glyoxal and 1.4 wt % acetol. The samples reacted for ˜3 days. Theresults are shown in Table 5.

TABLE 5 Hydroxyacetaldehyde and formaldehyde concentrations of aqueoussolutions after the addition of various amounts of glycine. GlycineHydroxyacetaldehyde (wt %) (wt %) Formaldehyde (wt %) Colour 7.0 14.0<0.2 Dark, red 4.8 20.0 <0.8 Dark, red 3.5 22.0 1.4 Dark, red

Comparing the results shown in Tables 4 and 5, although glycine reactswith formaldehyde to reduce the concentration of formaldehyde in theproduct aqueous solution, the reaction between glycine and formaldehydeis not as efficient as the reaction between cysteine and formaldehyde.Roughly twice as much glycine than cysteine was used to achievesubstantial removal of formaldehyde from the product aqueous solution(e.g. to reduce the concentration of formaldehyde in the aqueoussolution to <0.2 wt %).

Table 6 shows four examples of samples with diluted solutions ofhydroxyacetaldehyde. The water concentration in these samples is ˜90 wt%. Various weight percentages of glycine were admixed/dissolved asindicated below.

TABLE 6 Hydroxyacetaldehyde and formaldehyde concentrations of sampleaqueous solutions after the addition of various amounts of glycine.Sample 1 2 3 4 Glycine addition (wt %) none 0.33 0.88 1.8Hydroxyacetaldehyde (wt %) 5.46 5.38 5.01 4.27 Formaldehyde (wt %) 0.730.49 0.27 <0.2 Glyoxal (wt %) 0.42 0.35 0.24 0.18 Acetol (wt %) 0.350.30 0.30 0.31 Colour Light yellow Yellow Orange red

The solutions of Table 6 show that ˜1 mole of glycine (mw ˜75) reactswith ˜1.3 moles of formaldehyde while sacrificing ˜0.65 moles ofhydroxyacetaldehyde. Accordingly, more hydroxyacetaldehyde is sacrificedthan shown in Example 6 for cysteine.

Example 8

Raw pork sausages (product of Maple Leaf Co.) were inserted into theboiling hydroxyacetaldehyde/formaldehyde solution resulting from Example1, containing 3.8 wt % cysteine, diluted 25 times. The solution was agedfor approximately three days before being applied to pork sausages.

After approximately two minutes in the boiling solution, the sausageswere removed and visually inspected. The sausages were a brown “roasted”colour and were ready to be consumed. The overall look and taste of thesausages were very positive (e.g. the sausages had a non-descriptivemeaty flavor).

To compare the appearance of these sausages to traditional methods ofboiling raw pork sausages, raw pork sausages of the same type (productof Maple Leaf Co.) were prepared in boiled water only, again for twominutes.

After removal from the boiling water, the appearance and taste of thesausages was inspected. The appearance and taste of the sausages fromthe boiled water were inferior when compared to the appearance and tasteof the sausages boiled in the commercially-available solution mixed withcysteine. The sausages boiled in water only were described as tastingrather bland and they did not have the brown “roasted” colour of thesausages boiled in the solution resulting from Example 1.

While the above description provides examples of one or more methods orsystems, it will be appreciated that other methods or systems may bewithin the scope of the claims as interpreted by one of skill in theart.

What is claimed is:
 1. A method of browning a foodstuff comprising: a)preparing an aqueous solution of sugar carbonyls by pyrolysis of sugars,the sugar carbonyls comprising formaldehyde and hydroxyacetaldehyde, theaqueous solution having an initial concentration by weight offormaldehyde and an initial concentration by weight ofhydroxyacetaldehyde; b) adding cysteine to the aqueous solution; c)maintaining the aqueous solution at a temperature for a durationsufficient for the formaldehyde and the cysteine to react according to aMaillard reaction to produce melanoidins, a final concentration byweight of formaldehyde, and a final concentration by weight ofhydroxyacetaldehyde in the aqueous solution, wherein the finalconcentration by weight of formaldehyde is 50% or less than the initialconcentration by weight of formaldehyde and the final concentration byweight of hydroxyacetaldehyde is 50% or more than the initialconcentration by weight of hydroxyacetaldehyde; and d) heating theaqueous solution with the melanoidins, the final concentration offormaldehyde, and the final concentration of hydroxyacetaldehyde in thepresence of the foodstuff to brown the foodstuff.
 2. The method of claim1, wherein the final concentration by weight of formaldehyde is lessthan 10% of the initial concentration by weight of formaldehyde.
 3. Themethod of claim 1, wherein the final concentration by weight ofhydroxyacetaldehyde is more than 80% of the initial concentration byweight of hydroxyacetaldehyde.
 4. The method of claim 1, wherein a molarratio of the amount of the cysteine added to the aqueous solution to theinitial amount of formaldehyde is in a range of 1:2 to 1:10.
 5. Themethod of claim 1, wherein a molar ratio of the amount of the addedcysteine to the aqueous solution to the initial amount of formaldehydeis in a range of 1:3 to 1:5.
 6. The method of claim 2, wherein the finalconcentration by weight of hydroxyacetaldehyde is more than 80% of theinitial concentration by weight of hydroxyacetaldehyde.
 7. The method ofclaim 1, wherein the aqueous solution of sugar carbonyls obtained by thepyrolysis of sugars further comprises one or more selected from thegroup consisting of glyoxal, pyruvaldehyde, and acetol.
 8. The method ofclaim 7, wherein after the Maillard reaction, a combined totalconcentration of glyoxal, pyruvaldehyde, and acetol in the aqueoussolution is 1 to 10% by weight.
 9. The method of claim 1, wherein theaqueous solution of sugar carbonyls obtained by the pyrolysis of sugarsfurther comprises a combined total concentration of 1 to 20% by weightof one or more selected from the group consisting of glyoxal,pyruvaldehyde, and acetol.
 10. The method of claim 1, wherein theaqueous solution of sugar carbonyls obtained by the pyrolysis of sugarsfurther comprises glyoxal, pyruvaldehyde, and acetol.
 11. The method ofclaim 10, wherein after the Maillard reaction, a combined totalconcentration of glyoxal, pyruvaldehyde, and acetol in the aqueoussolution is 1 to 10% by weight of the aqueous solution.
 12. The methodof claim 1, wherein the aqueous solution of sugar carbonyls obtained bythe pyrolysis of sugars further comprises a combined total concentrationof 1 to 20% by weight of glyoxal, pyruvaldehyde, and acetol.
 13. Themethod of claim 1, wherein after the Maillard reaction, the aqueoussolution comprises from greater than 0 to 20% by weight of themelanoidins.
 14. The method of claim 1, wherein after the Maillardreaction, the aqueous solution comprises from 8 to 15% by weight of themelanoidins.
 15. The method of claim 13, wherein after the Maillardreaction, the final concentration of the hydroxyacetaldehyde is 4 to 50%by weight.
 16. The method of claim 14, wherein after the Maillardreaction, the final concentration of the hydroxyacetaldehyde is 4 to 50%by weight.
 17. A method of browning a foodstuff comprising: a) preparingan aqueous solution of sugar carbonyls by pyrolysis of sugars, the sugarcarbonyls comprising formaldehyde and hydroxyacetaldehyde, the aqueoussolution having an initial concentration by weight of formaldehyde andan initial concentration by weight of hydroxyacetaldehyde; b) addingglycine to the aqueous solution; c) maintaining the aqueous solution ata temperature for a duration sufficient for the formaldehyde and theglycine to react according to a Maillard reaction to producemelanoidins, a final concentration by weight of formaldehyde, and afinal concentration by weight of hydroxyacetaldehyde in the aqueoussolution, wherein the final concentration by weight of formaldehyde is50% or less than the initial concentration by weight of formaldehyde andthe final concentration by weight of hydroxyacetaldehyde is 50% or morethan the initial concentration by weight of hydroxyacetaldehyde; and d)heating the aqueous solution with the melanoidins, the finalconcentration of formaldehyde, and the final concentration ofhydroxyacetaldehyde in the presence of the foodstuff to brown thefoodstuff.
 18. The method of claim 17, wherein the final concentrationby weight of formaldehyde is less than 10% of the initial concentrationby weight of formaldehyde.
 19. The method of claim 17, wherein the finalconcentration by weight of hydroxyacetaldehyde is more than 80% of theinitial concentration by weight of hydroxyacetaldehyde.
 20. The methodof claim 17, wherein a molar ratio of the amount of the glycine added tothe aqueous solution to the initial amount of formaldehyde is in a rangeof 1:2 to 1:10.
 21. The method of claim 17, wherein a molar ratio of theamount of the glycine added to the aqueous solution to the initialamount of formaldehyde is in a range of 1:3 to 1:5.
 22. The method ofclaim 18, wherein the final concentration by weight ofhydroxyacetaldehyde is more than 80% of the initial concentration byweight of hydroxyacetaldehyde.
 23. The method of claim 17, wherein theaqueous solution of sugar carbonyls obtained by the pyrolysis of sugarsfurther comprises one or more selected from the group consisting ofglyoxal, pyruvaldehyde, and acetol.
 24. The method of claim 23, whereinafter the Maillard reaction, a combined total concentration of glyoxal,pyruvaldehyde, and acetol in the aqueous solution is 1 to 10% by weight.25. The method of claim 17, wherein the aqueous solution of sugarcarbonyls obtained by the pyrolysis of sugars further comprises acombined total concentration of 1 to 20% by weight of one or moreselected from the group consisting of glyoxal, pyruvaldehyde, andacetol.
 26. The method of claim 17, wherein the aqueous solution ofsugar carbonyls obtained by the pyrolysis of sugars further comprisesglyoxal, pyruvaldehyde, and acetol.
 27. The method of claim 26, whereinafter the Maillard reaction, a combined total concentration of glyoxal,pyruvaldehyde, and acetol in the aqueous solution is 1 to 10% by weightof the aqueous solution.
 28. The method of claim 17, wherein the aqueoussolution of sugar carbonyls obtained by the pyrolysis of sugars furthercomprises a combined total concentration of 1 to 20% by weight ofglyoxal, pyruvaldehyde, and acetol.
 29. The method of claim 17, whereinafter the Maillard reaction, the aqueous solution comprises from greaterthan 0 to 20% by weight of the melanoidins.
 30. The method of claim 17,wherein after the Maillard reaction, the aqueous solution comprises from8 to 15% by weight of the melanoidins.
 31. The method of claim 29,wherein after the Maillard reaction, the final concentration of thehydroxyacetaldehyde is 4 to 50% by weight.
 32. The method of claim 30,wherein after the Maillard reaction, the final concentration of thehydroxyacetaldehyde is 4 to 50% by weight.